A vector $\overrightarrow{\mathrm{A}}$ when added to the sum of the vectors $(\hat{\imath}-2 \hat{\jmath}+2…

A vector $\overrightarrow{\mathrm{A}}$ when added to the sum of the vectors $(\hat{\imath}-2 \hat{\jmath}+2 \hat{k})$ and $(-2 \hat{\imath}+\hat{\jmath}-\hat{k})$ gives a unit vector along $\mathrm{y}$ -axis. The magnitude of the vector $\overrightarrow{\mathrm{A}}$ is
  1. $\sqrt{3}$
  2. $\sqrt{6}$
  3. $\sqrt{8}$
  4. $\sqrt{10}$

Solution

$\vec{A}+(\hat{\imath}-2 \hat{\jmath}+2 \hat{k})+(-2 \hat{\imath}+\hat{\jmath}-\hat{k})=\frac{\hat{j}}{\begin{array}{l}\text { unit } \\ \text { vector along Y axis }\end{array}}$ $\vec{A}=\hat{\imath}+2 \hat{\jmath}-\hat{k}$ $|\vec{A}|=\sqrt{6}$

Asked in: MHT CET 2020 (14 Oct Shift 1)

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